Longer Breastfeeding Duration Is Associated With Decreased Risk of Hepatic Fibrosis Among Young Women With Nonalcoholic Fatty Liver Disease
Authors: Georgia Sofia Karachaliou, Ayako Suzuki, Vaishali A. Patel, Lori A. Bastian, Anna Mae Diehl, Manal F. Abdelmalek, Cynthia A. Moylan, Cynthia D. Guy, Ying Wang
Journal: Clinical Gastroenterology and Hepatology (2023)

Breastfeeding is widely recognized to exert various health benefits in infants and mothers (reviewed by Victora et al1Victora C.G. et al.Lancet. 2016; 387: 475-490Abstract Full Text Full Text PDF PubMed Scopus (3675) Google Scholar). Mothers who have breastfed are protected from metabolic syndrome and cardiovascular disease, however, some of the protective effects may decrease after the age of 50 years.2Nguyen B. et al.PLoS One. 2017; 12e0187923Google Scholar,3Natland S.T. et al.Int Breastfeed J. 2012; 7: 8Crossref PubMed Scopus (53) Google Scholar Breastfeeding also protects mothers and children from nonalcoholic fatty liver disease (NAFLD).4Ayonrinde O.T. et al.J Hepatol. 2017; 67: 568-576Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar,5Ajmera V.H. et al.J Hepatol. 2019; 70: 126-132Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar Whether breastfeeding protects women with NAFLD from disease progression and metabolic comorbidities and, if so, whether the protective effects depend on age, remain unknown. We conducted a cross-sectional analysis to evaluate the associations of live birth and cumulative lifetime breastfeeding with metabolic and histologic features in women with NAFLD and whether the effects were reduced among women older than age 50 years. A data set from the Duke University Health System NAFLD Clinical Database was analyzed, including 422 of 537 women with biopsy-proven NAFLD who also had provided reproductive information via standardized questionnaires. Metabolic and histologic features of NAFLD were collected at the time of the liver biopsy and evaluated for the associations with a history of live birth and cumulative duration of lactation while adjusting for other confounders using multiple linear, logistic, or ordinal logistic regression models, as appropriate. Details are provided in supplements (Supplementary Material). The median age at the time of liver biopsy was 52 years (interquartile range [IQR], 43–59 y); the majority (343; 81%) were white; the median body mass index (BMI) was 39 kg/m2 (IQR, 33–46 kg/m2); 199 (47%), 276 (65%), and 302 (72%) had type 2 diabetes mellitus (T2DM), hypertension, and hyperlipidemia, respectively; and 98 (23%) had advanced fibrosis. A total of 324 (77%) reported at least 1 live birth before the liver biopsy, 136 (43%) breastfed for more than 3 months, and 111 (35%) breastfed for more than 6 months. The clinical characteristics of the study population are summarized in Supplementary Table 1. After adjusting for covariates, parous women had a lower BMI than nonparous women, with an average difference in BMI of -2.7 (adjusted β ± SE, -2.70 ± 0.90; P = .003). No dose-dependency was observed between BMI and the number of liver birth(s). Other metabolic features were not associated significantly with either history of live birth or the cumulative duration of breastfeeding (Supplementary Table 2). Women who reported cumulative breastfeeding for 3 months or longer had a 36% decreased likelihood of advanced fibrosis than those who breastfed for fewer than 3 months (adjusted odds ratio [OR], 0.64; 95% CI, 0.42–0.98; P = .038). The protective effect was apparent among women age 50 years and younger, but disappeared among women older than age 50 years, at the time of liver biopsy (adjusted OR, 0.40; 95% CI, 0.20–0.78; P = .007 vs adjusted OR, 0.82; 95% CI, 0.47–1.42; P = .47). No associations with breastfeeding history were noted for steatosis, lobular inflammation, or hepatocyte ballooning. Overall, cumulative breastfeeding for 3 months or longer did not show a significant association with portal inflammation. Interestingly, young women who reported cumulative breastfeeding for 3 months or longer had a 63% decreased likelihood of portal inflammation than those who breastfed for fewer than 3 months, while the effect, again, was eliminated among women after age 50 years (adjusted OR, 0.37; 95% CI, 0.17– 0.79; P = .01 vs adjusted OR, 1.10; 95% CI, 0.57–1.94; P = .88). The results using a 6-month cut-off time for cumulative duration of lactation showed consistency (Table 1).Table 1Histologic Features and History of Live Birth(s)/BreastfeedingTotal, adjusted OR (95% CI), P valueAge ≤50 y, adjusted OR (95% CI), P valueAge >50 y, adjusted OR (95% CI), P valueSteatosis Live birth(s) (n = 324)0.80 (0.50–1.27), .340.68 (0.36–1.28), .230.88 (0.44–1.79), .73 Women with live birth(s)Breastfeeding ≥3 mo (n = 136)1.00 (0.64–1.54), .990.85 (0.43–1.65), .631.13 (0.63–2.02), .69Breastfeeding ≥6 mo (n = 111)0.94 (0.60–1.49), .800.95 (0.49–1.85), .880.92 (0.49–1.71), .78Hepatocyte ballooning Live birth(s) (n = 317)0.80 (0.49–1.30), .361.01 (0.50–2.05), .970.65 (0.32–1.32), .24 Women with live birth(s)Breastfeeding ≥3 mo (n = 132)0.77 (0.49–1.23), .280.66 (0.31–1.41), .280.82 (0.45–1.51), .53Breastfeeding ≥6 mo (n = 108)0.83 (0.51–1.34), .440.72 (0.33–1.55), .400.88 (0.46–1.65), .68Lobular inflammation Live birth(s) (n = 314)0.66 (0.39–1.10), .110.81 (0.39–1.65), .560.49 (0.23–1.02), .06 Women with live birth(s)Breastfeeding ≥3 mo (n = 134)1.25 (0.78–2.02), .351.96 (0.92–4.17), .080.92 (0.49–1.72), .79Breastfeeding ≥6 mo (n = 110)1.24 (0.76–2.04), .391.71 (0.81–3.62), .160.96 (0.50–1.88), .91Portal inflammation Live birth(s) (n = 317)1.12 (0.67–1.87), .671.09 (0.52–2.25), .821.11 (0.53–2.31), .78 Women with live birth(s)Breastfeeding ≥3 mo (n = 132)0.71 (0.44–1.14), .150.37 (0.17–0.79), .01aP < .05.1.10 (0.57–1.94), .88Breastfeeding ≥6 mo (n = 110)0.59 (0.36–0.97), .038aP < .05.0.32 (0.15–0.71), .005aP < .05.0.88 (0.46–1.68), .70Fibrosis Live birth(s) (n = 323)1.00 (0.64–1.57), .991.05 (0.56–1.97), .871.00 (0.52–1.94), .99 Women with live birth(s)Breastfeeding ≥3 mo (n = 135)0.64 (0.42–0.98), .038aP < .05.0.40 (0.20–0.78), <.007aP < .05.0.82 (0.47–1.42), .47Breastfeeding ≥6 mo (n = 111)0.71 (0.46–1.10), .120.52 (0.26–1.00), .0520.86 (0.48–1.53), .60NOTE. The models included the covariates, age at the time of liver biopsy (continuous variable), age category (using age 50 years as a proxy for menopause, age ≤50 years [ie, reproductive] vs >50 years [ie, postreproductive]), enrollment sites (liver clinic vs bariatric surgery), and race/ethnicity. Body mass index additionally was included in the models for live birth(s). No metabolic features were included in the models for breastfeeding because none of them showed associations with the cumulative duration of breastfeeding. Among women with a history of live birth(s) (n = 324), 7 patients did not have information for hepatocyte ballooning, 10 did not have information for lobular inflammation, 7 did not have information for portal inflammation, and 1 did not have information for hepatic fibrosis.OR, odds ratio.a P < .05. Open table in a new tab NOTE. The models included the covariates, age at the time of liver biopsy (continuous variable), age category (using age 50 years as a proxy for menopause, age ≤50 years [ie, reproductive] vs >50 years [ie, postreproductive]), enrollment sites (liver clinic vs bariatric surgery), and race/ethnicity. Body mass index additionally was included in the models for live birth(s). No metabolic features were included in the models for breastfeeding because none of them showed associations with the cumulative duration of breastfeeding. Among women with a history of live birth(s) (n = 324), 7 patients did not have information for hepatocyte ballooning, 10 did not have information for lobular inflammation, 7 did not have information for portal inflammation, and 1 did not have information for hepatic fibrosis. OR, odds ratio. Our cross-sectional study of women with a histologic diagnosis of NAFLD showed several significant associations of live birth and cumulative lifetime breastfeeding with metabolic and histologic features in women with NAFLD. Particularly, our analysis showed that parous women had a significantly lower BMI than nulliparous women, which may suggest that parity might have a protective effect against obesity. Obese women have a higher risk of infertility compared with women with a normal BMI, and are more likely to have polycystic ovarian syndrome.6Ramlau-Hansen C.H. et al.Hum Reprod. 2007; 22: 1634-1637Crossref PubMed Scopus (341) Google Scholar Given the cross-sectional nature of our study, whether parity has a protective effect or obesity itself results in infertility cannot be concluded in this study, pending future prospective studies that consider other factors (ie, polycystic ovarian syndrome and estrogen hormonal therapies). No associations were observed between other metabolic features (ie, T2DM, hypertension, and hyperlipidemia) and reported live birth or duration of lactation. Differences in the targeted population, the general population vs patients with a histologic diagnosis of NAFLD, or selection bias may explain the lack of protective effects of breastfeeding on metabolic features. Whether breastfeeding protects women with NAFLD from metabolic disorders remains to be evaluated in a prospective study. It is intriguing that breastfeeding had protective effects on portal inflammation and hepatic fibrosis, but not other key nonalcoholic steatohepatitis (NASH) features (eg, lobular inflammation or hepatocyte ballooning) and that the effects were observed only among women age 50 years or younger of age at the time of liver biopsy. Our group showed that nuclear accumulation of Yes-associated protein (YAP), a target of the Hippo kinase pathway, in ductal cells correlates with the intensity of ductular reactions, portal inflammation, and hepatic fibrosis in NASH livers.7Machado M.V. et al.J Hepatol. 2015; 63: 962-970Abstract Full Text Full Text PDF PubMed Scopus (93) Google Scholar Prolactin receptors have been reported to promote Hippo pathway activation in pancreatic cancer.8Nie H. et al.Theranostics. 2021; 11: 3898-3915Crossref PubMed Google Scholar Because the Hippo pathway suppresses YAP nuclear localization (reviewed by Werneburg et al9Werneburg N. et al.Gene Expr. 2020; 20: 67-74Crossref PubMed Scopus (12) Google Scholar), high prolactin levels related to lactation might promote YAP suppression and thereby inhibit the ductular reaction, portal inflammation, and hepatic fibrosis. Protective effects of prolactin on NAFLD also have been suggested in the literature,10Xu P. et al.BMC Gastroenterol. 2022; 22: 523Crossref PubMed Scopus (0) Google Scholar but the mechanisms are unknown. Further studies are needed determine if/how breastfeeding-related changes in prolactin regulate NAFLD progression because this information may enable more personalized approaches to NAFLD management in women of reproductive age. In summary, this cross-sectional analysis reports the protective effects of breastfeeding on histologic features of portal inflammation and fibrosis in adult parous women with biopsy-proven NAFLD. The study had several limitations, such as the inability to address the causality, lack of detailed information on breastfeeding (ie, exclusive vs combination with formula), recall bias, and cross-sectional data collection. However, these findings (mechanistic hypothesis and shortcomings of this study) will inform future experimental and prospective confirmatory studies to delineate the causality between breastfeeding and related hormonal milieu with NAFLD progression, advancing our knowledge of women-specific risk assessment and modification. The Duke Nonalcoholic Fatty Liver Disease Clinical Research Working Group included the following: Cynthia A. Moylan, Division of Gastroenterology, Department of Medicine, Duke University Medical Center, Durham, NC; Cynthia D. Guy, Department of Pathology, Duke University Medical Center, Durham, NC; and Ying Wang, Department of Biostatistics, Parexel International, Durham, NC. The authors wish to acknowledge Stephanie Buei, Linda Sanders, and YiPing Pan in supporting this study with the administration of patient questionnaires and/or data collection or management. The authors also acknowledge the Division of Metabolic and Weight Loss Surgery, Department of Surgery, and the Division of Endocrinology, Department of Internal Medicine, as well as the patients and their families who graciously volunteered to participate in the Duke Nonalcoholic Fatty Liver Disease Clinical Database with which this would not otherwise have been possible. This cross-sectional analysis used a data set from the Duke University Health System NAFLD Clinical Database. The database study is a prospective, open-enrolling study established in 2007 to collect clinical and research information from patients who had a clinically indicated liver biopsy for suspected NAFLD/NASH or underwent a liver biopsy at the time of bariatric surgery. Details regarding specific inclusion and exclusion criteria and histologic assessments in the NAFLD Clinical Database have been published previously.1Yang J.D. et al.Hepatology. 2014; 59: 1406-1414Crossref PubMed Scopus (208) Google Scholar,2Youssef N.A. et al.Liver Int. 2013; 33: 1062-1070Crossref PubMed Scopus (108) Google Scholar The Duke University Institutional Review Board approved the database study conducted under the Declaration of Helsinki on Ethical Principles for Medical Research Involving Human Subjects. The study population included 422 of 537 women in the overall database with biopsy-proven NAFLD between July 2007 and September 2019 who provided reproductive information via the standardized reproductive questionnaires. History of excessive alcohol use of 7 or more servings per week, serologic or histologic evidence of other co-existing diseases (viral hepatitis, primary biliary cirrhosis, autoimmune hepatitis, hemochromatosis, Wilson's disease, or α-1 antitrypsin deficiency), or previous liver transplantation were excluded. Our study outcomes were as follows: (1) metabolic features (ie, BMI, the presence of T2DM, hypertension, and hyperlipidemia), and (2) histologic features of NAFLD (ie, steatosis, lobular and portal inflammation, hepatocyte ballooning, and fibrosis stage), all of which were collected at the time of the liver biopsy. The diagnoses of metabolic disorders were based on physician diagnoses and treatment histories. Liver biopsy specimens were scored using the NASH Clinical Research Network scoring system.3Kleiner D.E. et al.Design and validation of a histological scoring system for nonalcoholic fatty liver disease.Hepatology. 2005; 41: 1313-1321Crossref PubMed Scopus (7513) Google Scholar The primary predictors were a history of live birth and cumulative duration of lactation (in months). The history of live births was treated as a binary variable, yes (≥1 live birth[s]) vs no. Cut-off times of 3 and 6 months were used for the cumulative duration of lactation, creating 2 binary variables.4Natland S.T. et al.Lactation and cardiovascular risk factors in mothers in a population-based study: the HUNT-study.Int Breastfeed J. 2012; 7: 8Crossref PubMed Scopus (53) Google Scholar,5Gunderson E.P. et al.Diabetes. 2010; 59: 495-504Crossref PubMed Scopus (194) Google Scholar The age at the time of the liver biopsy (continuous variable), age category (using age 50 years as a proxy for menopause,6Nichols H.B. et al.Am J Epidemiol. 2006; 164: 1003-1011Crossref PubMed Scopus (183) Google Scholar age ≤50 y [ie, reproductive] vs >50 y [ie, postreproductive]), enrollment sites (liver clinic vs bariatric surgery), and race/ethnicity were considered as covariates. Data are reported as means [IQR] for continuous variables and as percentages for categoric/binary variables (Supplementary Table 1). To evaluate the associations between metabolic features and the reproductive variables, we used multiple linear regression models for BMI and multiple logistic regression models for the presence of metabolic features. The models included one of the reproductive variables as a predictor and the covariates. To evaluate the associations between histologic features and the reproductive variables, we used multiple logistic (or ordinal logistic) regression models, including one of the reproductive variables and the covariates. Metabolic features were included in the model only when potential confounding effects were suspected. The analyses were performed in the entire data set and by age category. The statistical analysis was performed using JMP PRO 16 (SAS Institute, Inc, Cary, NC), and differences were considered statistically significant when P < .05. Because of the preliminary descriptive nature of this study, P values were not corrected for multiple comparisons.Supplementary Table 1Characteristics of the CohortDemographic/clinical, n (%) Age, y52 [43–59] White343 (81%) BMI, kg/m2aPatients with missing data: 2 for BMI, 7 for cumulative duration of breastfeeding, 10 for lobular inflammation, 9 for portal inflammation, 7 for hepatocytes ballooning, and 1 for fibrosis.39 [33–46] Type 2 diabetes mellitus199 (47%) Hypertension302 (72%) Hyperlipidemia276 (65%)Reproductive, n (%) Lifetime live birth, 0, 1, 2, >298 (23%), 85 (20%), 157 (37%), 82 (19%) Reported breastfeedingaPatients with missing data: 2 for BMI, 7 for cumulative duration of breastfeeding, 10 for lobular inflammation, 9 for portal inflammation, 7 for hepatocytes ballooning, and 1 for fibrosis.165 (51%)bAmong parous women. Cumulative breastfeeding duration0 [0–8]bAmong parous women. ≥3 mo136 (43%)bAmong parous women. ≥6 mo111 (35%)bAmong parous women.Histologic, n (%) Steatosis, 0, 1, 2, 38 (2%), 211 (50%), 122 (29%), 81 (19%) Lobular inflammation, 0, 1, 2, 3aPatients with missing data: 2 for BMI, 7 for cumulative duration of breastfeeding, 10 for lobular inflammation, 9 for portal inflammation, 7 for hepatocytes ballooning, and 1 for fibrosis.39 (10%), 273 (66%), 83 (20%), 17 (4%) Portal inflammation, 0, 1aPatients with missing data: 2 for BMI, 7 for cumulative duration of breastfeeding, 10 for lobular inflammation, 9 for portal inflammation, 7 for hepatocytes ballooning, and 1 for fibrosis.237 (57%), 176 (43%) Hepatocyte ballooning, 0, 1, 2aPatients with missing data: 2 for BMI, 7 for cumulative duration of breastfeeding, 10 for lobular inflammation, 9 for portal inflammation, 7 for hepatocytes ballooning, and 1 for fibrosis.155 (37%), 147 (36%), 113 (27%) Fibrosis, 0, 1, 2, 3, 4aPatients with missing data: 2 for BMI, 7 for cumulative duration of breastfeeding, 10 for lobular inflammation, 9 for portal inflammation, 7 for hepatocytes ballooning, and 1 for fibrosis.94 (22%), 142 (34%), 87 (21%), 83 (20%), 15 (3%)NOTE. The models included the covariates, age at the time of liver biopsy (continuous variable), age category (using age 50 years as a proxy for menopause, age ≤50 years [ie, reproductive] vs >50 years [ie, postreproductive]), enrollment sites (liver clinic vs bariatric surgery), and race/ethnicity.OR, odds ratio.NOTE. Median [25th–75th percentile].BMI, body mass index.a Patients with missing data: 2 for BMI, 7 for cumulative duration of breastfeeding, 10 for lobular inflammation, 9 for portal inflammation, 7 for hepatocytes ballooning, and 1 for fibrosis.b Among parous women. Open table in a new tab Supplementary Table 2Clinical Outcomes and History of Live Birth(s)/BreastfeedingTotal, β ± SE, P valueAge ≤50 y, β ± SE, P valueAge >50 y, β ± SE, P valueBody mass index Live birth(s) (n = 323)aOne woman with a history of live birth(s) did not have body mass index information.-2.70 ± 0.90, .003bP < .05.-2.94 ± 1.30, .025bP < .05.-2.40 ± 1.28, .062 Women with live birth(s)Breastfeeding ≥3 mo (n = 136)-0.49 ± 0.77, 0.53-2.00 ± 1.25, .110.54 ± 0.99, .58Breastfeeding ≥6 mo (n = 111)-0.66 ± 0.81, .41-1.91 ± 1.25, .130.26 ± 1.06, .81Type 2 diabetes mellitusTotal, adjusted OR (95% CI), P valueAge ≤50 y, adjusted OR (95% CI), P valueAge >50 y, adjusted OR (95% CI), P value Live birth(s) (n = 324)0.74 (0.45–1.20), .230.72 (0.36–1.43), .350.74 (0.36–1.51), .41 Women with live birth(s)Breastfeeding ≥3 mo (n = 136)1.09 (0.69–1.73), .710.88 (0.41–1.86), .731.17 (0.64–2.13), .61Breastfeeding ≥6 mo (n = 111)1.08 (0.67–1.74), .760.73 (0.34–1.55), .411.36 (0.71–2.58), .35Hypertension Live birth(s) (n = 324)0.64 (0.36–1.15), .130.46 (0.21–1.01), .0540.80 (0.31–2.10), .65 Women with live birth(s)Breastfeeding ≥3 mo (n = 136)0.96 (0.56–1.64), .880.75 (0.34–1.68), .491.13 (0.52–2.48), .75Breastfeeding ≥6 mo (n = 111)0.99 (0.57–1.72), .970.70 (0.31–1.55), .381.35 (0.57–3.17), .49Hyperlipidemia Live birth(s) (n = 324)0.83 (0.49–1.40), .480.92 (0.45–1.88), .810.59 (0.24–1.45), .25 Women with live birth(s)Breastfeeding ≥3 mo (n = 136)0.84 (0.51–1.37), .480.97 (0.45–2.08), .940.66 (0.34–1.30, .23Breastfeeding ≥6 mo (n = 111)0.66 (0.40–1.10), .110.73 (0.34–1.58), .430.53 (0.26–1.08), .08NOTE. The models included the covariates, age at the time of liver biopsy (continuous variable), age category (using age 50 years as a proxy for menopause, age ≤50 years [ie, reproductive] vs >50 years [ie, postreproductive]), enrollment sites (liver clinic vs bariatric surgery), and race/ethnicity.OR, odds ratio.NOTE. Median [25th–75th percentile].BMI, body mass index.a One woman with a history of live birth(s) did not have body mass index information.b P < .05. Open table in a new tab NOTE. The models included the covariates, age at the time of liver biopsy (continuous variable), age category (using age 50 years as a proxy for menopause, age ≤50 years [ie, reproductive] vs >50 years [ie, postreproductive]), enrollment sites (liver clinic vs bariatric surgery), and race/ethnicity. OR, odds ratio. NOTE. Median [25th–75th percentile]. BMI, body mass index. NOTE. The models included the covariates, age at the time of liver biopsy (continuous variable), age category (using age 50 years as a proxy for menopause, age ≤50 years [ie, reproductive] vs >50 years [ie, postreproductive]), enrollment sites (liver clinic vs bariatric surgery), and race/ethnicity. OR, odds ratio. NOTE. Median [25th–75th percentile]. BMI, body mass index.